FIG. 1 Prior Art
FIG. 1 shows a solar panel 105 has a conventional sun tracking system on it. The tracking system comprises four photo sensors 101,102,103,104 encircled by a sleeve 120. The four sensors locate in the center of the top surface of the solar panel 105. Photoelectric units 108 for collecting and converting solar energy into electricity are distributed on the top surface of the solar panel 105. The sleeve 120 has an opening for detecting the shift direction and distance of the movement of the sun through detecting the light intensity irradiating on each of the sensors. The traditional sleeve 120 has a wall with even height erected from the surface of the solar panel 105.
When the sun is above the solar panel 105, the light rays from the sun irradiate directly onto the solar panel 105, each of the four photo sensors is presumed to receive equal heat strength, or light intensity, from the sun. However, when the sun shifts left as shown in FIG. 1. the light rays below R1 are hindered by the wall and prevented from reaching to the photo sensors 101,102,103,104. A shadow is produced within the sleeve under R1, the shadow shall cover partially the photo sensors in the beginning and hence the light intensities sensed by the photo sensors are different from one another. FIG. 1 shows that sensor 101 is fully covered by the shadow, and sensors 102, 104 are partially covered by the shadow.
The light intensity of each of the photo sensors is sensed and transferred to a control unit (not shown). A mechanism deflects the solar panel 105 a calculated angle according to the information received from the control unit so that the solar panel 105 moves synchronically with the movement of the sun to receive relatively more solar energy.
The drawback of the prior art as shown in FIG. 1 is that the environmental light intensity of photo sensor 101 increases a little more than it should be by light reflection disturbance. See FIG. 1, a light ray R2 projects on the wall surface inside the sleeve 120 to produce a reflection light that directs to the sensor 101 to offset partially of the shadow covering the sensor 101 and thus decrease the light intensity around sensor 101.